Sheered Manifold Bolt #7 front

[papastruck]

Finally got around to tracking down an annoying exhaust leak. Went to undo the manifold bolts and one was hand tight. Hmmm. Pulled it out, and sure enough, it was sheered. From what I could tell before I dropped and lost the damned thing, it broke just inside flush with the cylinder head. Is there a chance, maybe with the inner fender pulled, to get at it without pulling the head? In case my cylinder numbering is off, it's driver side, 3rd back, front bolt.

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[Diesel_brad]

Finally got around to tracking down an annoying exhaust leak. Went to undo the manifold bolts and one was hand tight. Hmmm. Pulled it out, and sure enough, it was sheered. From what I could tell before I dropped and lost the damned thing, it broke just inside flush with the cylinder head. Is there a chance, maybe with the inner fender pulled, to get at it without pulling the head? In case my cylinder numbering is off, it's driver side, 3rd back, front bolt.

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Yup. If you have access to a right angle drill, that would be best.
I have had good results doing the following.

Find a drill bit that fits tight into the manifold hole.
Then (leave the manifold on for this step) use said drill bit and insert it into the manifold hole and drill into broken bolt/stud.This will make a centering point for a smaller drill bit.


Then remove the manifold. you will have a small concave dimple in the remaining bolt/stud. Liberall spray with PB blaser or equivalant

that will be your starting point to continue drill(with a smaller bit) Use a bit size for the eazy out you will be using. I reccomend getting a set of left hand drill bits. 80% of the time the left hand drill bits will walk the broken bolt/stud right out.

good luck, let us know how you make out

 

[papastruck]

That sounds like a plan - can knock off the pyro sender while I'm at it. Thanks for the info. Probably will be Memorial Day weekend before I get to it, but if I have success you'll probably hear me out the window.

 

[hesutton]

I'd use an end mill rather than a regular drill bit. It will not wonder over to the threads and will cut the old bolt quite well. That is what I used to remove a broken exhaust manifold bolt on my 6.9. But, I had the head off and on a drill press and used an end mill. Go slowly and check the work frequently. Once the old bolt is machined out, take a bottoming tap and chase the threads. Use a good coating of copper based anti-seize on the manifold bolts on reinstallation.

Heath

 

[towtruckdave]

All good advice so far....

but, when I found that on my 6.9, I jest blew it out with a cutting torch.

I do not know if you are comfortable doing it, but it can be done and it takes very little time.

 

[bike-maker]

The cutting torch trick is pretty cool when melting a bolt out of cast iron (don't try it on anything else). It takes quite a bit more heat to liquefy cast iron than the steel that bolts are made out of. I've always used it as a last resort; just in case I got things a little too hot.

 

[RLDSL]

Remember when you go to put the manifold back on to get new bolts and use the correct torque scale for teh bolts that you are using. I'd be willing to bet that a large percentage of teh exhaust manifold bolts out there are torqued incorrectly ( probably why so many seem to wind up with broken bolts)

You are supposed to get new bolts each time. You can either get the ones from ford for teh exhaust that are a prevailing torque thread ( oversize thread that distorts while torquing down to lock itself ) or you can use grade 8 bolts, but the book lists a different torque spec for each type of bolt. A new prevailing torque bolt requires more torque to overcome the distorted metal just to reach the same clamping force so if you use that torque spec on a grade 8 you will likely end up snapping the head off, inversely the grade 8 torque will leave a prevailing torque bolt loose to where it may rattle out, and reusing a prevailing torque bolt is a big no-no as it has already distorted itself and is now straightened out in the thread bore with minimal resistance

 

[papastruck]

Remember when you go to put the manifold back on to get new bolts and use the correct torque scale for teh bolts that you are using. I'd be willing to bet that a large percentage of teh exhaust manifold bolts out there are torqued incorrectly ( probably why so many seem to wind up with broken bolts)

You are supposed to get new bolts each time. You can either get the ones from ford for teh exhaust that are a prevailing torque thread ( oversize thread that distorts while torquing down to lock itself ) or you can use grade 8 bolts, but the book lists a different torque spec for each type of bolt. A new prevailing torque bolt requires more torque to overcome the distorted metal just to reach the same clamping force so if you use that torque spec on a grade 8 you will likely end up snapping the head off, inversely the grade 8 torque will leave a prevailing torque bolt loose to where it may rattle out, and reusing a prevailing torque bolt is a big no-no as it has already distorted itself and is now straightened out in the thread bore with minimal resistance

Which may explain why some of the bolts were surprisingly loose? I'll be getting new bolts, though now that I think about it, I can't for the life of me figure out how I'll get the torque wrench in there properly.

 

[papastruck]

All good advice so far....

but, when I found that on my 6.9, I jest blew it out with a cutting torch.

I do not know if you are comfortable doing it, but it can be done and it takes very little time.

Ahhhh, if only I had a cutting torch. Bummer.

Thanks for all the replies, guys. I'd felt pretty hopeless, but I'm ready to have at it and will post back with whatever carnage results.

 

[DeepRoots]

just be careful, old Iron gets crackly with a torch if it gets hot/cold too fast..... been there, done that, got a couple exhaust chunks on the bench to remind me.

 

[icanfixall]

What RLDSL posted is so correct. I found this out several years ago when I built my engine. I bought all the exhaust manifold bolts from ford parts online and glad I did.